1. Field of the Invention
The present invention relates to a capsule-type medical device which is passed through the body cavity and is capable of examination, therapy, and/or treatment.
2. Description of the Related Art
Capsule-type medical devices are known as medical devices which are swallowed by patients to pass through the body cavity tract, which can perform examination, therapy, and/or treatment.
Such capsule-type medical devices comprise treatment tools for performing such medical treatment, such as a medication-depositing unit for depositing medicine, treatment devices such as forceps or the like, treatment devices for performing incision or coagulation by ultrasonic or high-frequency means, and so forth, and are arranged to perform such medical treatment at an object portion in the body cavity tract. However, there are shortcomings within the capsule-type medical devices, such as requiring a long time to reach the object portion unless guided through the body cavity tract.
To deal with this problem, Japanese Patent Publication No. 3017770 discloses a capsule-type medical device comprising a magnet which is magnetically manipulated by a magnet outside of the body of the subject. With the medical device described in Japanese Patent Publication No. 3017770 (hereafter referred to simply as “No. 3017770”), an external uniform magnetic field uniaxially acts upon magnets provided on the outer perimeter of a capsule main body in the vertical direction, so that the capsule is guided through the body cavity tract without rotating, primarily. Also, an arrangement is also disclosed wherein an alternating magnetic field is applied externally, so as to rotate the main body. However, efficiently propelling rotational motion of the main unit is not easy.
Note that this No. 3017770 is equivalent to the Japanese Patent Application with Application No. H2-109696 (filed on Apr. 25, 1990) which is cited as proof of prior application in the later-described U.S. Pat. No. 5,681,260.
On the other hand, with the capsule-type medical device described in Japanese Unexamined Patent Application Publication No. 2001-179700 (hereafter referred to simply as “No. 2001-179700”), an external rotating magnetic field acts triaxially on a magnet provided within the capsule main unit in the vertical direction and horizontal direction, so as to gain propulsion by rotationally turning.
With the capsule-type medical device described in No. 2001-179700, a thrust generating unit which obtains propulsion by rotating is provided in the capsule main unit. However, with the capsule-type medical device described in No. 2001-179700, no consideration has been given to the internal structure of the capsule main unit with regard to rotations of the capsule main unit.
Accordingly, the capsule-type medical device described in No. 2001-179700 may make useless motions such as rotating eccentrically (zigzagging), and accordingly take time to reach the object position in the body cavity tract, rather than reaching the location smoothly.
Also, U.S. Pat. No. 5,353,807 discloses a configuration comprising a slender and flexible recovery member, a main unit disposed on the tip thereof for performing medical treatment, a coil provided on the circumference to the main unit for guiding with an eternal magnetic flux, and multiple propulsion plates provided on the recovering member, thereby enabling the direction of the main unit to be controlled by the magnetic polarity generated by the coil and the external magnetic flux, and further guiding the main unit through the body cavity by a propulsion plate provided on the recovering member.
This patent also discloses an arrangement of a main unit comprising an internal magnet and battery, with the capsule not being provided with the recovering member but rather guided by the external magnetic field.
However, with the arrangement described in this U.S. Patent, the direction of the magnetic polarity generated by the coil or the magnet is in the longitudinal direction of the main unit, so smooth propulsion by an external magnetic field is not easy.
Also, U.S. Pat. No. 5,681,260 also discloses a device wherein an endoscope insertion portion or the like is magnetically guided through the body cavity, besides the embodiment relating to FIGS. 50 through 76B corresponding to No. 3017770.
The arrangement described in this U.S. patent has a similar configuration as that in No. 3017770, and smooth propulsion of the endoscope insertion portion or the like is not easy.
Further, the above-described preceding examples do not disclose contents corresponding to the Claims of the Present Invention.